Field of the Invention
The present invention relates to a magnetic recording medium for high density recording, the medium comprising a ferromagnetic powder in a magnetic layer.
In general, with the demand for higher recording density of magnetic recording media for computer use, etc., it is necessary to yet further improve electromagnetic conversion characteristics, and it is important to make the ferromagnetic powder finer, the surface of the medium ultra smooth, etc.
With regard to finer magnetic substances, a recent magnetic substance employs a ferromagnetic metal powder of 0.1 μm or less or a ferromagnetic hexagonal ferrite powder having a plate size of 40 nm or less. In the case of a multilayer structure in which a magnetic layer is provided as an upper layer above a nonmagnetic lower layer provided on the surface of a support, in order to highly disperse a nonmagnetic powder used for the nonmagnetic layer or the magnetic substance a magnetic recording medium has been proposed that comprises a polycarboxylic acid or an anhydride thereof having a molecular weight of equal to or less than 300 in a magnetic layer (ref. JP-A-9-212847; JP-A denotes a Japanese unexamined patent application publication). There has also been proposed a magnetic recording medium comprising an organophosphorous compound in a magnetic layer (ref. JP-A-2001-338414).